1. Technical Field
The present invention relates to a secondary battery module containing a plurality of cells for a secondary battery inside of a container.
2. Description of Related Art
In a sodium/sulfur battery (hereinafter referred to as “NaS battery”) module containing a plurality of cells for an NaS battery inside of a container, operation is performed in the state in which the temperature of the cells is kept at as high as 300° C., and therefore, the cells are mostly contained inside of a heat insulating container. Moreover, gaps between the cells are filled with incombustible sand and an insulating plate is mostly interposed between the cells and the wall of the container in the NaS battery module so as to enhance safety.
In the meantime, the uniform temperature of the cells is required in the NaS battery module. Patent Document 1 proposes arranging cells flat, setting a heat insulating property of an upper wall and/or a lower wall to be lower than that of a side wall, and radiating heat mainly via the upper wall and/or the lower wall so as to achieve the uniform temperature of the cells. Moreover, Patent Document 1 refers to reducing the heat insulating property of the upper wall during electric discharging when an NaS battery generates heat (paragraph 0018).